1. Field of the Invention
This invention relates to novel organopolysiloxanes. More particularly, this invention relates to organopolysiloxanes prepared by the polymerization of certain disilyl substituted heterocyclic organic compounds wherein the silicon atoms are bonded to two carbon atoms of a 5-membered, ethylenically unsaturated heterocyclic ring containing oxygen, nitrogen or sulfur as the hetero atom.
2. Description of the Prior Art
Thiophenes and pyrroles wherein at least one of the cyclic carbon atoms is bonded to a silicon atom are reported in the literature.
U.S. Pat. No. 2,845,435, which issued to Frisch and Kary on July 29, 1958, discloses pyrrylsilanes of the general Formula 1. ##STR1## where R represents an aliphatic, aromatic or alicyclic hydrocarbon radical, n is 1, 2 or 3 and X represents a halogen atom. The compounds are prepared by reacting pyrrylmagnesium bromide with a halosilane such as methyltrichlorosilane.
Example IV of this patent describes the polymerization of 2-pyrrylmethyldichlorosilane to yield a polymer having pendant pyrryl groups along the siloxane chain as represented by formula 2. ##STR2## where Py represents the 2-pyrryl group.
Silyl-substituted thiophenes of the general formula ##STR3## where R represents a monovalent hydrocarbon radical, Z represents a hydrolyzable group and m and n represent the integer 1 or 2 are disclosed in U.S. Pat. No. 2,640,833, which issued to DiGiorgio on June 2, 1953. It will be apparent to those skilled in the art that compounds containing two hydrolyzable groups represented by Z can be condensed to yield diorganopolysiloxanes analogous to the pyrryl-substituted polymers represented by Formula 3. In this instance Py would represent a 2-thiophenyl group.
The nuclear magnetic resonance spectrum of 2,5-bis(dimethylhydroxysilyl)thiophene was investigated by V. A. Kuznetsov and coworkers and the results reported in the literature [Dokl. Akad. Nauk SSSR, volume 26, No. 5, pp. 1062-5]. No reactions or polymerization of this compound are disclosed.
The synthesis and platinum-catalyzed polymerization of 2-dimethylhydrosilyl-5-dimethylvinylsilylthiophene is reported by Tschernyschewa et al [Plaste Kausch. 10(7) 390 (1963)].
An objective of the present invention is to provide a novel class of organopolysiloxanes wherein at least a portion of the siloxane units contain a heterocyclic ring wherein two of the cyclic carbon atoms are bonded to silicon. A second objective of this invention is to provide a class of organopolysiloxanes exhibiting a resistance to degradation at temperatures of 300.degree. C. and above.